I tried using gcc 4.3.2 with binutils 2.19.51.20090116 (because the 2.19 release has issues on arm and I was too lazy to dig for the patch for it). Unfortunately, I error out right away with "as: unrecognized option '-mcpu=arm7tdmi'"

This was sort of abandoned for gcc 4.3 since it turned out there was a pretty bad bug
in it that would cause it to emit incorrect code that could not be assembled that is however fixed in 4.4
so it might be time to revisit this soon, anyway the pcfdriver patch has been comitted and hopefully the
patches removing tremor stuff from iram are no longer needed.

Michael, sorry fro the very late reply but others have been able to build with 4.4 for those arm7tdmi targets
so i would guess there's an issue with your setup.

New patch, for building with gcc 4.4.2 / binutils 2.20
This replaces all the earlier patches and is the only thing needed to build coldfire targets with this toolchain (tested with h300 only for now)
codec benchmarks show both speedups and slowdowns, more tweaking of optimization settings is needed.
The patch fixes compilation of the shorten codec, libmad and libtremor with this new toolchain, the libmad problem
is caused by the inline asm in synth_full() using too many registers (the function should probably be written in asm entirely) and tremor gets too large to fit in iram.
I also included tuning of the optimization setting for flac, it gives a significant speedup. (and changes flac from slowdown to speedup)

The tools patch adjusts configure and rockboxdev for the new toolchain.
the other patch tweaks the codec optimization settings for best performance when testing with the test_files

There are large speedups for aac and flac.
Small speedups for ac3, ape (mostly c1000), alac, atrac, cook, mpc
libmad is a little weird: mp3 is a little faster (3-5%), mp2 is ~10% faster but mp1 is 2-4% slower